Published WIPO patent application, WO03062668A1, entitled SNAP-FIT CHAIN GUIDE teaches a chain guide including a bracket adapted for being secured to an engine. The bracket includes a support surface including a leading end and a trailing end, and further includes a first saw-tooth fixing element. A guide shoe includes: (i) a shoe leading end; (ii) a shoe trailing end spaced from the shoe leading end in a chain movement direction; (iii) a chain guide surface extending between the shoe leading end and the shoe trailing end and adapted for slidably supporting an associated chain moving in the chain movement direction; and, (iv) an inner surface positioned adjacent the support surface of said bracket. The guide shoe further includes a second saw-tooth fixing element that mates with the first saw-tooth fixing element of the bracket to inhibit disconnection of the guide shoe and the bracket.
U.S. Pat. No. 6,302,816 entitled CHAIN GUIDE OR TENSIONER ARM WITH SHEET METAL BRACKET AND ALTERNATING TABS by Wigsten, Mark and assigned to BorgWarner Inc teaches a guide or tensioner arm including a bracket made from a formed sheet metal stamping. The bracket is formed of a body portion with a series of tabs formed along a bottom edge. The tabs are bent perpendicular to the body portion of the bracket in an alternating fashion. This forms a bracket having a T-shape providing a flat base for mounting a plastic shoe. Since the body portion is centered with respect to the alternating tabs a strong bracket for holding the plastic shoe is provided to guide or tension an associated strand of chain in a power transmission system.
Assembly of many plastic parts to other parts entail the use of a dart-type clip whereby a one-way tapered clip on the plastic part cantilevers into a locking position over a protrusion of the base part. The process of the cantilever spring portion of the clip bending to allow a taper to snap over the protrusion, places a tensile beam stress on the cantilevered spring. At times, the stress induced to the cantilevered spring necessary to clear the height of the protrusion can put high stresses on the cantilevered spring. Exposure to high stress can lead to reduced fatigue life of a part.